Available online 18 October 2023, 101933

Author links open overlay panel, , , , , , ABSTRACTObjectives

Accuracy is a crucial factor when assessing the quality of digital impressions. This systematic review aims to assess the accuracy of intraoral scan (IOS) in obtaining digital impressions of edentulous jaws.

Methods

This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42022382983). A thorough retrieval of seven electronic databases was undertaken, encompassing MEDLINE (PubMed), Web of Science, EMBASE, Scopus, Cochrane Library, Virtual Health Library, and Open Grey, through September 11, 2023. A snowball search was performed by tracing the reference lists of the included studies. The Population, Intervention, Comparison, and Outcome (PICO) question of this systematic review was: “What is the accuracy of intraoral scan in obtaining digital impressions of edentulous arches?” The Modified Methodological Index for Non-Randomized Studies (MINORS) was employed to assess the risk of bias.

Results

Among the studies retrieved from databases and manual search, a total of 25 studies were selected for inclusion in this systematic review, including 9 in vivo and 16 in vitro studies. Twenty-one of the included studies utilized the 3D deviation analysis method, while 4 studies employed the linear or angular deviation analysis method. The accuracy results of in vitro studies indicated a trueness range of 20-600 μm and a precision range of 2-700 μm. Results of in vivo studies indicated a trueness range of 40-1380 μm, while the precision results were not reported.

Conclusion

According to the results of this study, direct digital impressions by IOS cannot replace the conventional impressions of completely edentulous arches in vivo. Edentulous digital impressions by IOS demonstrated poor accuracy in peripheral areas with mobile tissues, such as the soft palate, vestibular sulcus, and sublingual area.

Section snippetsINTRODUCTION

With the popularization and development of computer-aided design and computer-aided manufacturing (CAD/CAM) technology in dentistry, the conventional prosthetic fabrication processes have gradually been replaced by digital technology. 1,2 To simplify and standardize the clinical process, many dentists have sought to establish and optimize fully digital clinical workflows for prosthesis fabrication. 3, 4, 5 The acquisition of accurate digital impressions, as the first step in the process, is

Protocol and Registration

This systematic review was conducted in accordance to the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) statement. After piloting of the study selection, we registered the protocol for this systematic review on the Prospectively Registered Systematic Reviews (PRSPERO) plat-form (www.crd.york.ac.uk/PROSPERO), under an ID: CRD42022382983.

Information Sources and Search Strategies

Electronic searching was conducted in seven databases: MEDLINE (PubMed), Web of Science, EMBASE, Scopus, Cochrane Library, Virtual

Study Selection Process

A total of 396 articles were initially retrieved from databases, of which 203 remained after removing duplicates. Subsequently, 176 articles were excluded after reading the title and abstract, and 6 articles were excluded after full text reading, 4 additional records were included through hand search. Finally, 25 articles met the inclusion criteria were included in this study. The screening process is illustrated in the flow diagram depicted in Figure 1.

General Characteristics of the Included Studies

Nine in vivo studies 35, 36, 37, 38, 39,

Results of Accuracy

The accuracy of the digital impressions is defined as “trueness” and “precision” (ISO 5725-1). Trueness is the difference between the IOS images and the actual anatomical morphology of the edentulous jaws. The better the trueness, the closer the scanned data are to the actual situation. Precision refers to the variation between the results of repeated scans of the same objects using the same IOS, and the better the precision, the better is the reproducibility of the IOS. 21,25 In addition to

DISCUSSION

The present study aimed to evaluate the accuracy of edentulous digital impressions obtained by IOS. The majority of the included in vitro studies utilized the digital data of the edentulous typodonts by lab scanners as reference data. According to the in vitro studies, the trueness results ranged from 20 μm to 600 μm, while the precision results ranged from 2μm to 700 μm. Nevertheless, it is important to note that these findings may not necessarily be relevant to clinical practice, due to the

CONCLUSION

Within the limitations of this study, direct IOS impressions cannot be recommended to replace traditional impressions of completely edentulous arches in vivo. In addition to the deficiency of accuracy, especially in peripheral areas, not being able to record the morphology and location of mobile tissues in their functional state posed another critical challenge for IOS in establishing a full digital workflow for complete denture manufacturing. More in vivo studies are needed to further clarify

SOURCE OF FUNDING

This work was supported by the Program for New Clinical Techniques and Therapies of PKUSS (PKUSSNCT-20B07), Key Research and Development Program of Shandong Province (2022CXGC020512). Table 4

AUTHOR CONTRIBUTIONS

Yiyang Wang: Conceptualization, Methodology, Study screening and reviewing, Data extraction, Quality assessment, Qualitative analysis, Writing –original draft. Yaning Li: Study screening and reviewing, Data extraction, Quality assessment. Shanshan Liang, Fusong Yuan and Yunsong Liu: Validation, Formal analysis, Writing – review & editing. Hongqiang Ye: Conceptualization, Methodology, Study screening and reviewing, Writing – review & editing. Yongsheng Zhou: Conceptualization, Writing – review &

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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